A vehicle seat is proposed that protects a portion of the neck of a passenger sitting in the seat when a collision with the vehicle occurs from the rear (hereinafter, referred to as a rear collision) (for example, see Patent Document 1).
The vehicle seat described in Patent Document 1 has a headrest on the upper edge of the seat back. Further, the seat back contains a stress transferring mechanism that works upon receiving a predetermined value or more of the impact load.
The seat back includes a pad member having a side pad member and a center pad member. Between the side pad member and the center pad member, a slit is provided so as to penetrate the pad member from the front side to the rear side. Then, with this slit, the side pad member and the center pad member are configured to have a divided formation (see FIG. 3 in Patent Document 1).
Further, the center pad member is provided with a slit that penetrates the center pad member from the front side to the rear side. With this slit, the center pad member is divided vertically into two pieces (see FIG. 4 of Patent Document 1).
If the vehicle is subjected to a rear collision, the upper body of the passenger is pressed rearward due to the impact load and sinks into the center pad member. Then, the center pad member is bent at the slit, and moves backward while the impact load occurring at the time of the rear collision is effectively transferred to the stress transferring mechanism such as a link mechanism by way of the center pad member. With the stress transferring mechanism operating due to the impact load, the headrest is moved upward while being moved toward the side of the head of the passenger.
As described above, the vehicle seat described in Patent Document 1 reliably receives the head portion of the passenger with the headrest at the time of rear collision, thereby protecting a portion of the neck of the passenger.